Implantable stents are devices that are placed in a body structure, such as a blood vessel or body cavity, to provide support and to maintain the structure open. Generally, implantable stents comprise a flexible tubular body composed of several individual rigid but flexible filament elements. In some stents, the filaments extend in helix configuration with a center line of the tubular body about a common axis. Typically, the filaments are woven into braided configurations that impart stability to the tubular body. The filaments can be arranged symmetrically wherein the number of filaments in each direction of a braid is divisible by two. The greater the diameter of the tubular body, the more filaments are used to give stability to the body.
Generally, the proper deployment of a stent in a body cavity, such as the esophagus, requires a medical practitioner to follow movement of the stent through the body to the precise position at which the stent is to be deployed. To that end, radiopaque stents have been developed that allow the medical practitioner to track the position of the stent during movement through the body using fluoroscope and/or x-ray devices.
The opacity of a stent image tends to vary with the material and type of process used to create the stent. For example, radiopacity may be limited by the location of radiopaque materials in the stent. Furthermore, introducing radiopaque materials into stent filaments can produce undesirable mechanical alterations to filament mechanical properties.
As such, there exists a need for an improved radiopaque polymeric stent that has greater radiopacity yet maintains its overall functionality during and after various medical procedures.